UUID Generator
Generate random UUID v4 identifiers instantly. Bulk create up to 100 at once.
What is a UUID and why would you need one?
A UUID (Universally Unique Identifier) is a 128-bit label that's practically guaranteed to be unique across every computer, database, and system on the planet—without needing a central authority handing them out. They look like this: 550e8400-e29b-41d4-a716-446655440000. The "v4" version you get from this tool is generated using random numbers, which means there are roughly 5.3 × 10^36 possible values. You could generate a billion UUIDs per second for 85 years and still have a less than 50% chance of a single duplicate.
Developers use UUIDs everywhere—database primary keys, API request identifiers, session tokens, file naming, microservice communication, and distributed systems. They're the go-to choice whenever you need an ID that won't collide with anyone else's, even if two completely separate systems are generating IDs at the same time with zero communication between them.
How this generator works under the hood
This tool uses your browser's built-in crypto.randomUUID() method when available, which provides cryptographically secure randomness. On older browsers, it falls back to crypto.getRandomValues()to fill a 16-byte array, then applies the RFC 4122 version 4 bit masks (setting the version nibble to 4 and the variant bits to 10). Everything runs 100% in your browser—no server calls, no data leaving your machine.
The formatting options are pure convenience. Removing hyphens gives you a compact 32-character hex string that's great for filenames or URL slugs. Uppercase is handy when you're working with systems like Windows GUIDs or certain SQL databases that store them in uppercase. Braces wrap the UUID in curly brackets, matching the format used by Microsoft's COM/OLE ecosystem and some legacy enterprise APIs.
Bulk generation and practical tips
Need to seed a test database with 100 unique records? Just bump the count to 100 and hit generate. You can copy the entire batch to your clipboard or download them as a plain text file. Each UUID lands on its own line, making it trivial to paste into a SQL insert statement, a JSON array, or a CSV file. Click any individual UUID in the list to copy just that one—handy when you only need to grab a specific entry.
One thing to keep in mind: UUIDs are great for uniqueness, but they're not great for sorting by creation time (unlike something like a ULID or Snowflake ID). If you need time-sortable unique IDs, a UUID v7 or ULID might be a better fit. But for the vast majority of use cases—API keys, database records, file identifiers, test fixtures—a standard v4 UUID from this tool is exactly what you need.